Density measuring apparatus



Sept. 1, 1942. H. E. 'r. HAULTAIN 2,294,455

' DENSITY MEASURING APPARATUS Filed D60. 20, 1939 Sheets-Sheet 1 p 942. H. E. 'r. HAULTAlN 2,294,455

DENSITY MEASURING APPARATUS Filed Dec. 20, 1939 2 Sheets-Sheet 2 Patented Sept. 1, 1942 UNITED STATES PATENT OFFIC Application December 20, 1939, Serial No. 310,141 In Canada December 7, 1939 12 Claims. (Cl. 265-44) This invention relates to density measuring apparatus used particularly to measure the density of ore pulp or the like flowing in launders. The object of my present invention is to devise simple apparatus of this character which will accurately measure and indicate the density of ore pulp as it continuously flows through the launders for conveying the pulp from one machine to another so that variations may be quickly detected and the necessary correction made to maintain an even grade of pulp to the mill machinery whereby it will operate consistently at all times.

I attain my objects by providing means spaced slightly from the bottom of the launder and extending longitudinally thereof to divide the flow of pulp therethrough into upper and lower portions. In most launders the flow is rapid and the pulp is agitated during its transference from a machine to a launder or from one launder to another which results in the formation of small air bubbles in the pulp or in the formation of a sort of froth on the upper surface of the pulp. By removing a continuous sample of the pulp from beneath the dividing means, constructing the latter to ensure the sample taken from the lower portion of the pulp will be free of bubbles, and providing means for measuring the density of the sample, an accurate indication of variations of the density of the flow through the launder will .be made.

The constructions are hereinafter more fully described and areillustrated in the accompanying drawings in which- Fig. 1 is a diagrammatical view showing one form of the apparatus;

Fig. 2 a cross-section on the line 22 in Fig. 1;

Fig. 3 a diagrammatic view of a modified form of the apparatus;

Fig. .4 Ya diagrammatic view of another modified form;

Fig. 5 a similar view of a further modification; and

Fig. 6 a plan view of the deflector, plate and part ,of the launder shown inFigs. 4 and 5.

In the drawings like numerals of reference indicate corresponding parts in the different figures.

l is an inclined launder for conveying ore pulp 2 from one machine to another. The ore pulp not only flows rapidly through each launder l but is agitated therein, when it is transferred thereto from a machine, a down-pipe or another launder, which results in small air bubbles 3 being formed in the pulp 2. To obtain an accurate measurement of the density 'of such pulp, it is essential that a sample containing no air bubbles be tested. This is accomplished by providing a device 4 for dividing the flow of pulp in the launder to separate the upper portion, which contains practically all of the air bubbles, from the lower portion which contains comparatively none or very few of such bubbles. The device 4 may be a shallow inverted V shaped plate 4*, as shown in Figs. 1, 2 and 3 which extends lengthwise of the launder and is spaced slightly from the bottom thereof. The sample is withdrawn through a conduit 5 which communicates with the space beneath the plate 4 the communication being adjacent the bottom of the launder and the downstream end of the plate. Since the latter is positioned beneath the upper portion of the pulp, the velocity of the pulp beneath the plate is reduced by friction so that any bubbles in the lower portion of the fluent material will move more readily upwardly into contact with the plate. The latter thus serves to collect any 'air bubbles in the lower portion and to divert them to the apex of the plate so that they will unite to form large bubbles which move along the underside thereof at the maximum distance from the level of the conduit communication. The large bubbles have less tendency than small bubbles to be carried by the smaller flow into the conduit. Thus no air bubbles will enter thevertical conduit 5 which, in these figures, depends from the launder.

' Any known apparatus for indicating the density of the pulp sample flowing through the conduit 5 may be employed. In Fig. 1, two spaced apart air tubes 6, 1 communicate with the conduit at different levels. The tubes are provided with constrictions 8, 9 and are connected with an air supply pipe In which is provided with a constant pressure valve II and a control valve l2 whereby an even flow of air from each tube is permitted to bubble through the pulp in the conduit 5. The legs of a differential manometer l3 are connected with the tubes 6, 1 whereby the manometer will measure and indicate the difference in pressures. This differential pressure is a continuous indication of the density of the sample of the pulp flowing through the conduit 5 and thus of the pulp flowing through the launder I. The flow through the conduit is regulated by means-of a discharge pipe l5 which is arranged relative'to the conduit to form a U tube therewith. The diameter of the discharge pipe is less than that of the conduit whereby the velocity of, flow through the pipe is increased to ensure the solid particles of the pulp, which tendto settle, will be carried with the liquid thereof around the bends of the discharge pipe leading to the outlet I4.

In Fig. 3, the conduit forms the discharge leg of the U tube which includes the inlet leg I5 The latter is smaller in diameter than the conduit 5 and communicates with a short length of pipe 26 which communicates with the bottom of the launder I. The diameter of the pipe 26 is substantially the same as that of the conduit 5 or 5 in Fig. 1, so that the communication between the launder and the conduit will not become choked by any foreign material in the pulp. Due to the decreased size of the leg IS the velocity of flow therethrough is increased to ensure that the sands will be carried through the U tube. The upper end of the conduit 5 continuously overflows into a receptacle or trough l6 so that a constant head of the pulp is main tained in the conduit. Thus, only one air tube 6 is required to measure the density and said tube is provided with a constriction 8 and is connected with an air supply pipe III similar to the pipe Hi. The tube 6 is connected with a manometer l3 and with a recording instrument IT.

in certain cases it is practically impossible to withdraw a sample of the pulp through the bottom of the launder l and to meet these conditions I have devised the following apparatus shown in Figs. 4, 5 and 6. The U tube including the conduit 5 and the pipe I5 is connected with a syphon which includes a pipe 26 which communicates with the space beneath a shallow V shaped plate 4*. The pipe 26 extends downwardly through the upper open end of the launder and passes through the plate on its longitudinal center line. Any air bubbles in the lowerportion of the pulp beneath the plate 4* will rise to the margins of the plate and thus away from the level of the communication with the conduit. A deflector I8-having streamlined sides I9 is secured to the upper surface of the plate 4 to surround the part of the pipe 26'" extending above the plate and through the upper portion of the pulp. The deflector enables thepulp to flow smoothly past the pipe without creating any disturbance such as would occur if the pulp contacted the wall of the pipe. In this case, a constant head of pulp is also maintained in the conduit 5 so that, if desired, only one air tub-e 6 may be employed. The tube is provided with a constriction 8 and is connected with an air supply pipe If! and a manometer l3".

While any suitable means such as a rubber suction bulb communicating with the upper end of V the pipe 26 may be employed to prime the syphon, I prefer to use a continuously operating vacuum system for automatically priming the syphon whenever it is required to be primed. To a suction line 21 connected with a vacuum pump not shown and provided with a restricted orifice 28, is connected a length of tubing 29 having a -relief valve 30 therein. The tubing 29 communicates with a jar 31 with which also communicates another piece of tubing 32 which is connected with a glass tube 33. The latter communicates with the upper end of the pipe 26 The relief valve is so adjusted that the partial vacuum in the glass tube 33 is just sufficient to raise the pulp about one foot above the pipe 26 The jar 3! serves as a safety device to trap any pulp accidentally drawn thereinto to prevent it from reaching the restricted orifice.

In Fig. 5, all of the conduit 5 is above the level of the launder and its outlet may be directed by a pipe or hose I5 back into the launder. The lower end of the conduit passes through the streamlined deflector 18 and the plate 4 to communicate with the space beneath the latter. Said deflector and plate are similar to the deflector and plate l8 and 4 respectively. A pressure water jet 2| of small size in the upper end of the conduit serves as an injector to maintain a constant flow of pulp therethrough. A suction bulb 20 may be provided to start the flow through the conduit. Two tubes 22 and 23 communicating with the conduit at different levels are provided with constrictions 24, 25 which communicate with the atmosphere. These constrictions permit only a very small quantity of air to be drawn, by the suction created in the conduit, through each tube from which it bubbles into the conduit. A manometer l3 connected across the tubes 22, 23 indicates the diflerential pressure of the tubes and thus the density of the pulp flowing through the launder.

It will be distinctly understood that various modifications may be made without departing from the spirit of my invention.

What I claim as my invention is:

1. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a shallow inverted V shaped plate slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few air bubbles; a conduit in communication with the launder adjacent its bottom for continuously carrying a sample of the material from said lower portion, the conduit being located intermediate the ends of the said plate and centrally of the apex thereof, the plate being positioned beneath the upper portion of the fluent material thus reducing the velocity of the material beneath the plate so that any bubbles in the lower portion of the fluent material will move upwardly into contact with the plate and thereafter be diverted to the apex of the plate and be united to form large bubbles having less tendency than small bubbles to be carried with the smaller flow intothe conduit; and means for indicating the density of the material in the, conduit.

2. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a shallow V shaped plate slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few air bubbles; means forcontinuously drawing a sample of the material from the lower portion, the said means including a conduit opening through the plate on its longitudinal center line to communicate with the space beneath it, the conduit being located intermediate the ends of the plate and the latter being positioned beneath the upper portion of the fluent material thus reducing the velocity of the material beneath the plate so that any bubbles in the lower portion of the fluent material will move upwardly into contact with the plate, the plate being adapted to collect any'air bubbles in the lower portion and to divert them to the margins of the plate and thus away from the level of the conduit communication; and means for indicating the density of the material in the conduit.

3. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a V shaped deflector having a bottom spaced slightly from the bottom of the launder and beneath the upper surface of the material to divide the flow of material through the launder into upper and lower portions; means for continuously drawing a sample of the material flowing beneath the bottom of the deflector including a conduit opening therethrough on its longitudinal center line to communicate with the space beneath the bottom of the deflector, the deflector having streamlined sides surrounding the part of the conduit extending through the upper portion of the material so that the flow of said upper portion will be deflected laterally with a minimum of disturbance; and means for indicating the density of the material in the conduit.

4. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a shallow V shaped plate slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing the air bubbles from the lower-portion; means for continuously drawing a sample of the material from the lower portion, the said means including a conduit opening through the plate on its longitudinal center line to communicate with the space beneath it, the plate being adapted to collect any air bubbles in the lower portion and to divert them to the margins of the plate and thus away from the level of the conduit communication; a streamlined deflector secured to the upper surface of the plate to surround the part of the conduit extending through the upper portion of the material above the plate so that said portion will have a minimum of disturbance; and means for indicating the density of the material in the conduit.

5. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a shallow V shaped plate slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few air bubbles; a conduit passed through the plate on its longitudinal center line to communicate with the space beneath the plate; an injector communicating with the conduit for causing the fluent material from the said lower portion to flow through the conduit; and means for indicating the density of the material in the conduit.

6. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a V shaped deflector slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few air bubbles; means for creating a suction to continuously draw a sample of the material from the lower portion, the said means including a conduit opening through the deflector on its longitudinal center line to communicate with the space therebeneath, the conduit having a negative pressure therein; means for determining the density of a stratum of the materialin the conduit between two vertically spaced apart points, the last mentioned means, including two tubes communicating with the interior of the conduit at the said points and having restricted communications with the atmosphere so that a minute volume of air will be drawn by the negative pressur in the conduit through each tube into said conduit; and means connected with said tubes to indicate the differential pressures therein.

7; Apparatus of the class described compris-' ing" an inclined launder for conveying fluent material containing air bubbles; a V shaped deflector slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few air bubbles; means including a syphon for drawing a sample of the material from the lower portion, the last mentioned means including a conduit opening through the deflector on its longitudinal center line to communicate with the space therebeneath; restricted means connected with a continuous source of vacuum and with the conduit for automatically priming the said syphon; and means for indicating the density of the material in the conduit.

8. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a device having its undersurface provided with two upwardly inclined portions, the device extending lengthwise of the launder spaced slightly from its bottom for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few air bubbles; a conduit for continuously carrying a sample of the material from said lower portion, the conduit being located intermediate the ends of the device and centrally of the said upwardly inclined portions, the conduit forming one leg of a U tube, the other leg and the bend between said legs being of less diameter than the conduit to increase the velocity of the flow therethrough; and means for indicating the density of the; material in the conduit.

9. Apparatus of the class described comprising an inclined launder for conveying fluent material containing air bubbles; a V shaped deflector slightly spaced from the bottom of the launder and extending lengthwise thereof for dividing the flow of material therethrough to separate the upper portion containing more of the air bubbles from the lower portion containing relatively few bubbles; a conduit passed through the deflector on its longitudinal center line to communicate with the space beneath the deflector; an injector communicating with the conduit for causing the material from the said portion to flow therethrough; means for indicating the density of the material in the conduit; and a streamlined deflector secured to the upper surface of the first deflector to surround the part of the conduit extending through the upper portion of the material above the first deflector so that said portion will have a minimum of disturbance.

10. Apparatus of the class described comprising an inclined launder for conveying fluent material; a conduit having its lower end slightly spaced from the bottom of the launder to carry a part of the lower portion of the fluent material'from the launder; aninjector communicating with the conduitfor causing: the: material:

in said lower portion to .flow through the conduit; means for indicating the density of the material in the conduit; anda streamlined: deflector disposed on the lower end of the-conduit extending through the upper portion of the fluent material so that the said upperv portion will have a minimum of disturbance;

11. Apparatus of the class described comprising an inclined launder for conveyinglfluent" positioned beneath the upper portion of the fluent material thus reducing the velocity of the material beneath the device so thatany bubbles in said lower portion of the fluent'material will movemoreireadily upwardly into contact with the ,device and i'thereafter move upwardly on one of said inclinedportionsaway from the conduit.

l2.tAp.paratus ofthe class described compris- 1 ing'; an inclined launder for conveying fluent material containing-air bubbles; a device having its undersurface provided with two upwardly inclined-portions; the device extending lengthwise of the launder'and'spaced slightly from its bot- .tom for dividing" the flow of material therethrough-to separate theupper portion containing more of the air bubbles from the lower portion" containing relatively few air bubbles; a conduitin communication with the space beneath the said device forcontinuously, carrying a sample of thegmaterial" from said lower portion, the communication being located adjacent the downstream end-of the dividing means and centrally of the said upwardlyinclined portions; and means for indicating the-density of the material in the conduit, the device being positioned beneaththe upper portion of the fluent material thusreducing the velocity, of the material beneath the device so that any bubbles in said lower portion of' the fluent material will move more readily upwardly into contact with the device and thereafter move upwardly on one of said inclinedportions; away from the conduit.

HERBERT E. T. HAULTAIN. 

